The Content Indexing link is under the Administration section farther down on the left-hand menu:image2015-7-27 9:30:1.png
You could use Ctrl+F to search for this on the page if you are getting lost with all the options along the left.
Once you're on the Content Indexing page, click the Rebuild button:
Hi my Community friends! For those who don't know me, I'm a product marketer on the Confluence Cloud team - nice to meet you! For those of you who do, you know that I've been all up in your Co...
Connect with like-minded Atlassian users at free events near you!Find a group
Connect with like-minded Atlassian users at free events near you!
Unfortunately there are no AUG chapters near you at the moment.Start an AUG
You're one step closer to meeting fellow Atlassian users at your local meet up. Learn more about AUGs